This invention relates to a variable displacement pump.
U.S. Patent Application Publication No. 2008/0118381 (corresponding to Japanese Patent Application Publication No. 2008-115706) discloses a variable displacement vane pump. In this variable displacement vane pump, a region of a substantially half of circumference with respect to a rotational direction of a rotor is a suction region, and a region of a substantially half of circumference is a discharge region.